/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2017, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 */

#define DEBUG_SUBSYSTEM S_SEC

#include <libcfs/libcfs.h>
#include <linux/crypto.h>
#include <linux/key.h>

#include <obd.h>
#include <obd_class.h>
#include <obd_support.h>
#include <lustre_net.h>
#include <lustre_import.h>
#include <lustre_log.h>
#include <lustre_disk.h>
#include <lustre_dlm.h>
#include <uapi/linux/lustre/lustre_param.h>
#include <lustre_sec.h>

#include "ptlrpc_internal.h"

const char *sptlrpc_part2name(enum lustre_sec_part part)
{
        switch (part) {
        case LUSTRE_SP_CLI:
                return "cli";
        case LUSTRE_SP_MDT:
                return "mdt";
        case LUSTRE_SP_OST:
                return "ost";
        case LUSTRE_SP_MGC:
                return "mgc";
        case LUSTRE_SP_MGS:
                return "mgs";
        case LUSTRE_SP_ANY:
                return "any";
        default:
                return "err";
        }
}
EXPORT_SYMBOL(sptlrpc_part2name);

enum lustre_sec_part sptlrpc_target_sec_part(struct obd_device *obd)
{
        const char *type = obd->obd_type->typ_name;

        if (!strcmp(type, LUSTRE_MDT_NAME))
                return LUSTRE_SP_MDT;
        if (!strcmp(type, LUSTRE_OST_NAME))
                return LUSTRE_SP_OST;
        if (!strcmp(type, LUSTRE_MGS_NAME))
                return LUSTRE_SP_MGS;

        CERROR("unknown target %p(%s)\n", obd, type);
        return LUSTRE_SP_ANY;
}

/****************************************
 * user supplied flavor string parsing  *
 ****************************************/

/*
 * format: <base_flavor>[-<bulk_type:alg_spec>]
 */
int sptlrpc_parse_flavor(const char *str, struct sptlrpc_flavor *flvr)
{
        char            buf[32];
        char           *bulk, *alg;

        memset(flvr, 0, sizeof(*flvr));

        if (str == NULL || str[0] == '\0') {
                flvr->sf_rpc = SPTLRPC_FLVR_INVALID;
                return 0;
        }

	strlcpy(buf, str, sizeof(buf));

        bulk = strchr(buf, '-');
        if (bulk)
                *bulk++ = '\0';

        flvr->sf_rpc = sptlrpc_name2flavor_base(buf);
        if (flvr->sf_rpc == SPTLRPC_FLVR_INVALID)
                goto err_out;

        /*
         * currently only base flavor "plain" can have bulk specification.
         */
        if (flvr->sf_rpc == SPTLRPC_FLVR_PLAIN) {
                flvr->u_bulk.hash.hash_alg = BULK_HASH_ALG_ADLER32;
                if (bulk) {
                        /*
                         * format: plain-hash:<hash_alg>
                         */
                        alg = strchr(bulk, ':');
                        if (alg == NULL)
                                goto err_out;
                        *alg++ = '\0';

                        if (strcmp(bulk, "hash"))
                                goto err_out;

                        flvr->u_bulk.hash.hash_alg = sptlrpc_get_hash_alg(alg);
                        if (flvr->u_bulk.hash.hash_alg >= BULK_HASH_ALG_MAX)
                                goto err_out;
                }

                if (flvr->u_bulk.hash.hash_alg == BULK_HASH_ALG_NULL)
                        flvr_set_bulk_svc(&flvr->sf_rpc, SPTLRPC_BULK_SVC_NULL);
                else
                        flvr_set_bulk_svc(&flvr->sf_rpc, SPTLRPC_BULK_SVC_INTG);
        } else {
                if (bulk)
                        goto err_out;
        }

        flvr->sf_flags = 0;
        return 0;

err_out:
        CERROR("invalid flavor string: %s\n", str);
        return -EINVAL;
}
EXPORT_SYMBOL(sptlrpc_parse_flavor);

/****************************************
 * configure rules                      *
 ****************************************/

static void get_default_flavor(struct sptlrpc_flavor *sf)
{
        memset(sf, 0, sizeof(*sf));

        sf->sf_rpc = SPTLRPC_FLVR_NULL;
        sf->sf_flags = 0;
}

static void sptlrpc_rule_init(struct sptlrpc_rule *rule)
{
	rule->sr_netid = LNET_NET_ANY;
	rule->sr_from = LUSTRE_SP_ANY;
	rule->sr_to = LUSTRE_SP_ANY;
	rule->sr_padding = 0;

	get_default_flavor(&rule->sr_flvr);
}

/*
 * format: network[.direction]=flavor
 */
int sptlrpc_parse_rule(char *param, struct sptlrpc_rule *rule)
{
	char *flavor, *dir;
	int rc;

	sptlrpc_rule_init(rule);

	flavor = strchr(param, '=');
	if (flavor == NULL) {
		CERROR("invalid param, no '='\n");
		RETURN(-EINVAL);
	}
	*flavor++ = '\0';

	dir = strchr(param, '.');
	if (dir)
		*dir++ = '\0';

	/* 1.1 network */
	if (strcmp(param, "default")) {
		rule->sr_netid = libcfs_str2net(param);
		if (rule->sr_netid == LNET_NET_ANY) {
			CERROR("invalid network name: %s\n", param);
			RETURN(-EINVAL);
		}
	}

	/* 1.2 direction */
	if (dir) {
		if (!strcmp(dir, "mdt2ost")) {
			rule->sr_from = LUSTRE_SP_MDT;
			rule->sr_to = LUSTRE_SP_OST;
		} else if (!strcmp(dir, "mdt2mdt")) {
			rule->sr_from = LUSTRE_SP_MDT;
			rule->sr_to = LUSTRE_SP_MDT;
		} else if (!strcmp(dir, "cli2ost")) {
			rule->sr_from = LUSTRE_SP_CLI;
			rule->sr_to = LUSTRE_SP_OST;
		} else if (!strcmp(dir, "cli2mdt")) {
			rule->sr_from = LUSTRE_SP_CLI;
			rule->sr_to = LUSTRE_SP_MDT;
		} else {
			CERROR("invalid rule dir segment: %s\n", dir);
			RETURN(-EINVAL);
		}
	}

	/* 2.1 flavor */
	rc = sptlrpc_parse_flavor(flavor, &rule->sr_flvr);
	if (rc)
		RETURN(-EINVAL);

	RETURN(0);
}
EXPORT_SYMBOL(sptlrpc_parse_rule);

void sptlrpc_rule_set_free(struct sptlrpc_rule_set *rset)
{
	LASSERT(rset->srs_nslot ||
		(rset->srs_nrule == 0 && rset->srs_rules == NULL));

	if (rset->srs_nslot) {
		OBD_FREE_PTR_ARRAY(rset->srs_rules, rset->srs_nslot);
		sptlrpc_rule_set_init(rset);
	}
}
EXPORT_SYMBOL(sptlrpc_rule_set_free);

/*
 * return 0 if the rule set could accomodate one more rule.
 */
int sptlrpc_rule_set_expand(struct sptlrpc_rule_set *rset)
{
	struct sptlrpc_rule *rules;
	int nslot;

	might_sleep();

	if (rset->srs_nrule < rset->srs_nslot)
		return 0;

	nslot = rset->srs_nslot + 8;

	/* better use realloc() if available */
	OBD_ALLOC_PTR_ARRAY(rules, nslot);
	if (rules == NULL)
		return -ENOMEM;

	if (rset->srs_nrule) {
		LASSERT(rset->srs_nslot && rset->srs_rules);
		memcpy(rules, rset->srs_rules,
		       rset->srs_nrule * sizeof(*rset->srs_rules));

		OBD_FREE_PTR_ARRAY(rset->srs_rules, rset->srs_nslot);
	}

	rset->srs_rules = rules;
	rset->srs_nslot = nslot;
	return 0;
}

static inline int rule_spec_dir(struct sptlrpc_rule *rule)
{
	return (rule->sr_from != LUSTRE_SP_ANY ||
		rule->sr_to != LUSTRE_SP_ANY);
}
static inline int rule_spec_net(struct sptlrpc_rule *rule)
{
	return (rule->sr_netid != LNET_NET_ANY);
}
static inline int rule_match_dir(struct sptlrpc_rule *r1,
                                 struct sptlrpc_rule *r2)
{
	return (r1->sr_from == r2->sr_from && r1->sr_to == r2->sr_to);
}
static inline int rule_match_net(struct sptlrpc_rule *r1,
                                 struct sptlrpc_rule *r2)
{
	return (r1->sr_netid == r2->sr_netid);
}

/*
 * merge @rule into @rset.
 * the @rset slots might be expanded.
 */
int sptlrpc_rule_set_merge(struct sptlrpc_rule_set *rset, 
                           struct sptlrpc_rule *rule)
{
	struct sptlrpc_rule      *p = rset->srs_rules;
	int                       spec_dir, spec_net;
	int                       rc, n, match = 0;

	might_sleep();

	spec_net = rule_spec_net(rule);
	spec_dir = rule_spec_dir(rule);

        for (n = 0; n < rset->srs_nrule; n++) {
                p = &rset->srs_rules[n]; 

                /* test network match, if failed:
                 * - spec rule: skip rules which is also spec rule match, until
                 *   we hit a wild rule, which means no more chance
                 * - wild rule: skip until reach the one which is also wild
                 *   and matches
                 */
                if (!rule_match_net(p, rule)) {
                        if (spec_net) {
                                if (rule_spec_net(p))
                                        continue;
                                else
                                        break;
                        } else {
                                continue;
                        }
                }

                /* test dir match, same logic as net matching */
                if (!rule_match_dir(p, rule)) {
                        if (spec_dir) {
                                if (rule_spec_dir(p))
                                        continue;
                                else
                                        break;
                        } else {
                                continue;
                        }
                }

                /* find a match */
                match = 1;
                break;
        }

        if (match) {
                LASSERT(n >= 0 && n < rset->srs_nrule);

                if (rule->sr_flvr.sf_rpc == SPTLRPC_FLVR_INVALID) {
                        /* remove this rule */
                        if (n < rset->srs_nrule - 1)
                                memmove(&rset->srs_rules[n],
                                        &rset->srs_rules[n + 1],
                                        (rset->srs_nrule - n - 1) *
                                        sizeof(*rule));
                        rset->srs_nrule--;
                } else {
                        /* override the rule */
                        memcpy(&rset->srs_rules[n], rule, sizeof(*rule));
                }
        } else {
                LASSERT(n >= 0 && n <= rset->srs_nrule);

                if (rule->sr_flvr.sf_rpc != SPTLRPC_FLVR_INVALID) {
                        rc = sptlrpc_rule_set_expand(rset);
                        if (rc)
                                return rc;

                        if (n < rset->srs_nrule)
                                memmove(&rset->srs_rules[n + 1],
                                        &rset->srs_rules[n],
                                        (rset->srs_nrule - n) * sizeof(*rule));
                        memcpy(&rset->srs_rules[n], rule, sizeof(*rule));
                        rset->srs_nrule++;
                } else {
                        CDEBUG(D_CONFIG, "ignore the unmatched deletion\n");
                }
        }

        return 0;
}
EXPORT_SYMBOL(sptlrpc_rule_set_merge);

/**
 * given from/to/nid, determine a matching flavor in ruleset.
 * return 1 if a match found, otherwise return 0.
 */
int sptlrpc_rule_set_choose(struct sptlrpc_rule_set *rset,
			    enum lustre_sec_part from,
			    enum lustre_sec_part to,
			    lnet_nid_t nid,
			    struct sptlrpc_flavor *sf)
{
	struct sptlrpc_rule *r;
	int n;

	for (n = 0; n < rset->srs_nrule; n++) {
		r = &rset->srs_rules[n];

		if (LNET_NIDNET(nid) != LNET_NET_ANY &&
		    r->sr_netid != LNET_NET_ANY &&
		    LNET_NIDNET(nid) != r->sr_netid)
			continue;

		if (from != LUSTRE_SP_ANY && r->sr_from != LUSTRE_SP_ANY &&
		    from != r->sr_from)
			continue;

		if (to != LUSTRE_SP_ANY && r->sr_to != LUSTRE_SP_ANY &&
		    to != r->sr_to)
			continue;

		*sf = r->sr_flvr;
		return 1;
	}

	return 0;
}

void sptlrpc_rule_set_dump(struct sptlrpc_rule_set *rset)
{
        struct sptlrpc_rule *r;
        int     n;

        for (n = 0; n < rset->srs_nrule; n++) {
                r = &rset->srs_rules[n];
                CDEBUG(D_SEC, "<%02d> from %x to %x, net %x, rpc %x\n", n,
                       r->sr_from, r->sr_to, r->sr_netid, r->sr_flvr.sf_rpc);
        }
}

static int sptlrpc_rule_set_extract(struct sptlrpc_rule_set *gen,
                                    struct sptlrpc_rule_set *tgt,
                                    enum lustre_sec_part from,
                                    enum lustre_sec_part to,
                                    struct sptlrpc_rule_set *rset)
{
	struct sptlrpc_rule_set *src[2] = { gen, tgt };
	struct sptlrpc_rule     *rule;
	int                      i, n, rc;

	might_sleep();

	/* merge general rules firstly, then target-specific rules */
	for (i = 0; i < 2; i++) {
		if (src[i] == NULL)
			continue;

                for (n = 0; n < src[i]->srs_nrule; n++) {
                        rule = &src[i]->srs_rules[n];

                        if (from != LUSTRE_SP_ANY &&
                            rule->sr_from != LUSTRE_SP_ANY &&
                            rule->sr_from != from)
                                continue;
                        if (to != LUSTRE_SP_ANY &&
                            rule->sr_to != LUSTRE_SP_ANY &&
                            rule->sr_to != to)
                                continue;

                        rc = sptlrpc_rule_set_merge(rset, rule);
                        if (rc) {
                                CERROR("can't merge: %d\n", rc);
                                return rc;
                        }
                }
        }

        return 0;
}

/**********************************
 * sptlrpc configuration support  *
 **********************************/

struct sptlrpc_conf_tgt {
	struct list_head              sct_list;
        char                    sct_name[MAX_OBD_NAME];
        struct sptlrpc_rule_set sct_rset;
};

struct sptlrpc_conf {
	struct list_head	sc_list;
	char			sc_fsname[MTI_NAME_MAXLEN];
	unsigned int		sc_modified;	/* modified during updating */
	unsigned int		sc_updated:1,	/* updated copy from MGS */
				sc_local:1;	/* local copy from target */
	struct sptlrpc_rule_set	sc_rset;	/* fs general rules */
	struct list_head	sc_tgts;	/* target-specific rules */
};

static struct mutex sptlrpc_conf_lock;
static LIST_HEAD(sptlrpc_confs);

static void sptlrpc_conf_free_rsets(struct sptlrpc_conf *conf)
{
	struct sptlrpc_conf_tgt *conf_tgt, *conf_tgt_next;

	sptlrpc_rule_set_free(&conf->sc_rset);

	list_for_each_entry_safe(conf_tgt, conf_tgt_next,
				 &conf->sc_tgts, sct_list) {
		sptlrpc_rule_set_free(&conf_tgt->sct_rset);
		list_del(&conf_tgt->sct_list);
		OBD_FREE_PTR(conf_tgt);
	}
	LASSERT(list_empty(&conf->sc_tgts));

	conf->sc_updated = 0;
	conf->sc_local = 0;
}

static void sptlrpc_conf_free(struct sptlrpc_conf *conf)
{
	CDEBUG(D_SEC, "free sptlrpc conf %s\n", conf->sc_fsname);

	sptlrpc_conf_free_rsets(conf);
	list_del(&conf->sc_list);
	OBD_FREE_PTR(conf);
}

static
struct sptlrpc_conf_tgt *sptlrpc_conf_get_tgt(struct sptlrpc_conf *conf,
                                              const char *name,
                                              int create)
{
        struct sptlrpc_conf_tgt *conf_tgt;

	list_for_each_entry(conf_tgt, &conf->sc_tgts, sct_list) {
                if (strcmp(conf_tgt->sct_name, name) == 0)
                        return conf_tgt;
        }

        if (!create)
                return NULL;

        OBD_ALLOC_PTR(conf_tgt);
        if (conf_tgt) {
		strlcpy(conf_tgt->sct_name, name, sizeof(conf_tgt->sct_name));
                sptlrpc_rule_set_init(&conf_tgt->sct_rset);
		list_add(&conf_tgt->sct_list, &conf->sc_tgts);
        }

        return conf_tgt;
}

static
struct sptlrpc_conf *sptlrpc_conf_get(const char *fsname,
                                      int create)
{
        struct sptlrpc_conf *conf;

	list_for_each_entry(conf, &sptlrpc_confs, sc_list) {
                if (strcmp(conf->sc_fsname, fsname) == 0)
                        return conf;
        }

        if (!create)
                return NULL;

        OBD_ALLOC_PTR(conf);
        if (conf == NULL)
                return NULL;

	if (strlcpy(conf->sc_fsname, fsname, sizeof(conf->sc_fsname)) >=
	    sizeof(conf->sc_fsname)) {
		OBD_FREE_PTR(conf);
		return NULL;
	}
        sptlrpc_rule_set_init(&conf->sc_rset);
	INIT_LIST_HEAD(&conf->sc_tgts);
	list_add(&conf->sc_list, &sptlrpc_confs);

        CDEBUG(D_SEC, "create sptlrpc conf %s\n", conf->sc_fsname);
        return conf;
}

/**
 * caller must hold conf_lock already.
 */
static int sptlrpc_conf_merge_rule(struct sptlrpc_conf *conf,
                                   const char *target,
                                   struct sptlrpc_rule *rule)
{
        struct sptlrpc_conf_tgt  *conf_tgt;
        struct sptlrpc_rule_set  *rule_set;

        /* fsname == target means general rules for the whole fs */
        if (strcmp(conf->sc_fsname, target) == 0) {
                rule_set = &conf->sc_rset;
        } else {
                conf_tgt = sptlrpc_conf_get_tgt(conf, target, 1);
                if (conf_tgt) {
                        rule_set = &conf_tgt->sct_rset;
                } else {
                        CERROR("out of memory, can't merge rule!\n");
                        return -ENOMEM;
                }
        }

        return sptlrpc_rule_set_merge(rule_set, rule);
}

/**
 * process one LCFG_SPTLRPC_CONF record. if \a conf is NULL, we
 * find one through the target name in the record inside conf_lock;
 * otherwise means caller already hold conf_lock.
 */
static int __sptlrpc_process_config(char *target, const char *fsname,
				    struct sptlrpc_rule *rule,
				    struct sptlrpc_conf *conf)
{
	int rc;

	ENTRY;
	if (!conf) {
		if (!fsname)
			return -ENODEV;

		mutex_lock(&sptlrpc_conf_lock);
		conf = sptlrpc_conf_get(fsname, 0);
		if (!conf) {
			CERROR("can't find conf\n");
			rc = -ENOMEM;
		} else {
			rc = sptlrpc_conf_merge_rule(conf, target, rule);
		}
		mutex_unlock(&sptlrpc_conf_lock);
	} else {
		LASSERT(mutex_is_locked(&sptlrpc_conf_lock));
		rc = sptlrpc_conf_merge_rule(conf, target, rule);
	}

	if (!rc)
		conf->sc_modified++;

	RETURN(rc);
}

int sptlrpc_process_config(struct lustre_cfg *lcfg)
{
	char fsname[MTI_NAME_MAXLEN];
	struct sptlrpc_rule rule;
	char *target, *param;
	int rc;

	print_lustre_cfg(lcfg);

	target = lustre_cfg_string(lcfg, 1);
	if (!target) {
		CERROR("missing target name\n");
		return -EINVAL;
	}

	param = lustre_cfg_string(lcfg, 2);
	if (!param) {
		CERROR("missing parameter\n");
		return -EINVAL;
	}

	/* parse rule to make sure the format is correct */
	if (strncmp(param, PARAM_SRPC_FLVR,
		    sizeof(PARAM_SRPC_FLVR) - 1) != 0) {
		CERROR("Invalid sptlrpc parameter: %s\n", param);
		return -EINVAL;
	}
	param += sizeof(PARAM_SRPC_FLVR) - 1;

	CDEBUG(D_SEC, "processing rule: %s.%s\n", target, param);

	/*
	 * Three types of targets exist for sptlrpc using conf_param
	 * 1.	'_mgs' which targets mgc srpc settings. Treat it as
	 *	as a special file system name.
	 * 2.	target is a device which can be fsname-MDTXXXX or
	 *	fsname-OSTXXXX. This can be verified by the function
	 *	server_name2fsname.
	 * 3.	If both above conditions are not meet then the target
	 *	is a actual filesystem.
	 */
	if (server_name2fsname(target, fsname, NULL))
		strlcpy(fsname, target, sizeof(target));

	rc = sptlrpc_parse_rule(param, &rule);
	if (rc)
		return rc;

	return __sptlrpc_process_config(target, fsname, &rule, NULL);
}
EXPORT_SYMBOL(sptlrpc_process_config);

static int logname2fsname(const char *logname, char *buf, int buflen)
{
        char   *ptr;
        int     len;

        ptr = strrchr(logname, '-');
        if (ptr == NULL || strcmp(ptr, "-sptlrpc")) {
                CERROR("%s is not a sptlrpc config log\n", logname);
                return -EINVAL;
        }

        len = min((int) (ptr - logname), buflen - 1);

        memcpy(buf, logname, len);
        buf[len] = '\0';
        return 0;
}

void sptlrpc_conf_log_update_begin(const char *logname)
{
        struct sptlrpc_conf *conf;
        char                 fsname[16];

        if (logname2fsname(logname, fsname, sizeof(fsname)))
                return;

	mutex_lock(&sptlrpc_conf_lock);

        conf = sptlrpc_conf_get(fsname, 0);
	if (conf) {
		if (conf->sc_local) {
			LASSERT(conf->sc_updated == 0);
			sptlrpc_conf_free_rsets(conf);
		}
		conf->sc_modified = 0;
	}

	mutex_unlock(&sptlrpc_conf_lock);
}
EXPORT_SYMBOL(sptlrpc_conf_log_update_begin);

/**
 * mark a config log has been updated
 */
void sptlrpc_conf_log_update_end(const char *logname)
{
        struct sptlrpc_conf *conf;
        char                 fsname[16];

        if (logname2fsname(logname, fsname, sizeof(fsname)))
                return;

	mutex_lock(&sptlrpc_conf_lock);

        conf = sptlrpc_conf_get(fsname, 0);
        if (conf) {
                /*
                 * if original state is not updated, make sure the
                 * modified counter > 0 to enforce updating local copy.
                 */
                if (conf->sc_updated == 0)
                        conf->sc_modified++;

                conf->sc_updated = 1;
        }

	mutex_unlock(&sptlrpc_conf_lock);
}
EXPORT_SYMBOL(sptlrpc_conf_log_update_end);

void sptlrpc_conf_log_start(const char *logname)
{
        char                 fsname[16];

        if (logname2fsname(logname, fsname, sizeof(fsname)))
                return;

	mutex_lock(&sptlrpc_conf_lock);
        sptlrpc_conf_get(fsname, 1);
	mutex_unlock(&sptlrpc_conf_lock);
}
EXPORT_SYMBOL(sptlrpc_conf_log_start);

void sptlrpc_conf_log_stop(const char *logname)
{
        struct sptlrpc_conf *conf;
        char                 fsname[16];

        if (logname2fsname(logname, fsname, sizeof(fsname)))
                return;

	mutex_lock(&sptlrpc_conf_lock);
        conf = sptlrpc_conf_get(fsname, 0);
        if (conf)
                sptlrpc_conf_free(conf);
	mutex_unlock(&sptlrpc_conf_lock);
}
EXPORT_SYMBOL(sptlrpc_conf_log_stop);

static void inline flavor_set_flags(struct sptlrpc_flavor *sf,
                                    enum lustre_sec_part from,
                                    enum lustre_sec_part to,
                                    unsigned int fl_udesc)
{
        /*
         * null flavor doesn't need to set any flavor, and in fact
         * we'd better not do that because everybody share a single sec.
         */
        if (sf->sf_rpc == SPTLRPC_FLVR_NULL)
                return;

        if (from == LUSTRE_SP_MDT) {
                /* MDT->MDT; MDT->OST */
                sf->sf_flags |= PTLRPC_SEC_FL_ROOTONLY;
        } else if (from == LUSTRE_SP_CLI && to == LUSTRE_SP_OST) {
                /* CLI->OST */
                sf->sf_flags |= PTLRPC_SEC_FL_ROOTONLY | PTLRPC_SEC_FL_BULK;
        } else if (from == LUSTRE_SP_CLI && to == LUSTRE_SP_MDT) {
                /* CLI->MDT */
                if (fl_udesc && sf->sf_rpc != SPTLRPC_FLVR_NULL)
                        sf->sf_flags |= PTLRPC_SEC_FL_UDESC;
        }

	/* Some flavors use a single uid (0) context */
	if (flvr_is_rootonly(sf->sf_rpc))
		sf->sf_flags |= PTLRPC_SEC_FL_ROOTONLY;

	/* User descriptor might need to be cleared */
	if (flvr_allows_user_desc(sf->sf_rpc) == 0)
		sf->sf_flags &= ~PTLRPC_SEC_FL_UDESC;
}

void sptlrpc_conf_choose_flavor(enum lustre_sec_part from,
                                enum lustre_sec_part to,
                                struct obd_uuid *target,
                                lnet_nid_t nid,
                                struct sptlrpc_flavor *sf)
{
        struct sptlrpc_conf     *conf;
        struct sptlrpc_conf_tgt *conf_tgt;
        char                     name[MTI_NAME_MAXLEN];
        int                      len, rc = 0;

	obd_uuid2fsname(name, target->uuid, sizeof(name));

	mutex_lock(&sptlrpc_conf_lock);

        conf = sptlrpc_conf_get(name, 0);
        if (conf == NULL)
                goto out;

        /* convert uuid name (supposed end with _UUID) to target name */
        len = strlen(target->uuid);
        LASSERT(len > 5);
        memcpy(name, target->uuid, len - 5);
        name[len - 5] = '\0';

        conf_tgt = sptlrpc_conf_get_tgt(conf, name, 0);
        if (conf_tgt) {
                rc = sptlrpc_rule_set_choose(&conf_tgt->sct_rset,
                                             from, to, nid, sf);
                if (rc)
                        goto out;
        }

        rc = sptlrpc_rule_set_choose(&conf->sc_rset, from, to, nid, sf);
out:
	mutex_unlock(&sptlrpc_conf_lock);

        if (rc == 0)
                get_default_flavor(sf);

        flavor_set_flags(sf, from, to, 1);
}

/**
 * called by target devices, determine the expected flavor from
 * certain peer (from, nid).
 */
void sptlrpc_target_choose_flavor(struct sptlrpc_rule_set *rset,
                                  enum lustre_sec_part from,
                                  lnet_nid_t nid,
                                  struct sptlrpc_flavor *sf)
{
        if (sptlrpc_rule_set_choose(rset, from, LUSTRE_SP_ANY, nid, sf) == 0)
                get_default_flavor(sf);
}

#define SEC_ADAPT_DELAY         (10)

/**
 * called by client devices, notify the sptlrpc config has changed and
 * do import_sec_adapt later.
 */
void sptlrpc_conf_client_adapt(struct obd_device *obd)
{
	struct obd_import  *imp;
	int rc;
	ENTRY;

	LASSERT(strcmp(obd->obd_type->typ_name, LUSTRE_MDC_NAME) == 0 ||
		strcmp(obd->obd_type->typ_name, LUSTRE_OSC_NAME) == 0 ||
		strcmp(obd->obd_type->typ_name, LUSTRE_OSP_NAME) == 0 ||
		strcmp(obd->obd_type->typ_name, LUSTRE_LWP_NAME) == 0);
	CDEBUG(D_SEC, "obd %s\n", obd->u.cli.cl_target_uuid.uuid);

	/* serialize with connect/disconnect import */
	with_imp_locked_nested(obd, imp, rc, OBD_CLI_SEM_MDCOSC) {
		write_lock(&imp->imp_sec_lock);
		if (imp->imp_sec)
			imp->imp_sec_expire = ktime_get_real_seconds() +
				SEC_ADAPT_DELAY;
		write_unlock(&imp->imp_sec_lock);
	}

	EXIT;
}
EXPORT_SYMBOL(sptlrpc_conf_client_adapt);

/**
 * called by target devices, extract sptlrpc rules which applies to
 * this target, to be used for future rpc flavor checking.
 */
int sptlrpc_conf_target_get_rules(struct obd_device *obd,
				  struct sptlrpc_rule_set *rset)
{
	struct sptlrpc_conf *conf;
	struct sptlrpc_conf_tgt *conf_tgt;
	enum lustre_sec_part sp_dst;
	char fsname[MTI_NAME_MAXLEN];
	int rc = 0;
	ENTRY;

	if (strcmp(obd->obd_type->typ_name, LUSTRE_MDT_NAME) == 0) {
		sp_dst = LUSTRE_SP_MDT;
	} else if (strcmp(obd->obd_type->typ_name, LUSTRE_OST_NAME) == 0) {
		sp_dst = LUSTRE_SP_OST;
	} else {
		CERROR("unexpected obd type %s\n", obd->obd_type->typ_name);
		RETURN(-EINVAL);
	}

	obd_uuid2fsname(fsname, obd->obd_uuid.uuid, sizeof(fsname));

	mutex_lock(&sptlrpc_conf_lock);
	conf = sptlrpc_conf_get(fsname, 0);
	if (conf == NULL) {
		CERROR("missing sptlrpc config log\n");
		rc = -EFAULT;
	} else {
		/* extract rule set for this target */
		conf_tgt = sptlrpc_conf_get_tgt(conf, obd->obd_name, 0);

		rc = sptlrpc_rule_set_extract(&conf->sc_rset,
				      conf_tgt ? &conf_tgt->sct_rset : NULL,
				      LUSTRE_SP_ANY, sp_dst, rset);
	}
	mutex_unlock(&sptlrpc_conf_lock);

	RETURN(rc);
}

int  sptlrpc_conf_init(void)
{
	mutex_init(&sptlrpc_conf_lock);
	return 0;
}

void sptlrpc_conf_fini(void)
{
	struct sptlrpc_conf  *conf, *conf_next;

	mutex_lock(&sptlrpc_conf_lock);
	list_for_each_entry_safe(conf, conf_next, &sptlrpc_confs, sc_list)
		sptlrpc_conf_free(conf);
	LASSERT(list_empty(&sptlrpc_confs));
	mutex_unlock(&sptlrpc_conf_lock);
}
